A Study to Investigate the Radiological Onset of Action After Treatment Initiation With Subcutaneous (SC) Natalizumab in Participants With Relapsing-Remitting Multiple Sclerosis (RRMS)

The primary objective of this study is to evaluate the radiological efficacy of SC natalizumab over time through Week 24 in natalizumab-naïve participants, as measured by brain magnetic resonance imaging (MRI). The secondary objectives of this study are to evaluate additional lesion-related radiological efficacy measures over time, relapse-based clinical efficacy measures, disability improvement and worsening (EDSS), pharmacokinetic and pharmacodynamic parameters, the immunogenicity of repeated doses, and safety in treatment-naïve participants of SC natalizumab.